Final answer:
It is true that when a frog is in anoxic water, reducing blood flow through the skin can minimize oxygen loss from the blood to the water, supporting the frog's reliance on breathing air for oxygen.
Step-by-step explanation:
When a frog sits in anoxic water, where oxygen levels are significantly low, they can obtain enough oxygen by breathing air using their lungs. Under these conditions, it is indeed true that it makes sense to reduce blood flow through the skin to minimize the loss of oxygen from the blood to the water. Frogs and other amphibians can perform gas exchange through their moist skin, a process called cutaneous respiration, but when the water is anoxic, the skin may lose more oxygen to the water than it gains. Therefore, reducing blood flow to the skin while increasing air-breathing efforts would be a suitable adaptive response.